This invention relates to shock absorbers and more particularly to shock absorbers that capture energy resulting from the relative motion of a vehicle's suspension system.
It is known that automobiles are inefficient, wasting over 80% of the energy stored in the fuel as heat. Thus eight of every ten gallons in the vehicle's tank don't help propel the vehicle.
Automobile manufacturers have made costly strides to improve fuel economy. For example, regenerative braking is standard on many hybrid automobiles. Car makers also spend a great deal of effort to reduce wind drag so as to improve fuel economy through streamlined, low drag automobile body designs. Manufacturers also use lighter, yet more expensive, materials to reduce vehicle weight to reduce fuel consumption.
Motor vehicles include a suspension system to control vertical motion of the wheel with respect to the vehicle. In addition to springs, shock absorbers are provided to provide damping. The energy removed from a conventional suspension system is lost as heat. There are known systems that attempt to recover suspension system energy. For example, U.S. Pat. No. 7,261,171 teaches a mechanical arrangement in which reciprocating movements of a wheel relative to a vehicle body are converted to rotations of an armature of a generator to produce electricity for recharging the battery of the vehicle. Another electromechanical regenerative system is disclosed in U.S. Pat. No. 5,570,286 that utilizes a magnet moving in relation to conductive coils.
United States published pending Application No. U.S. 2007/0089924 A1 discloses an hydraulic system for recovering energy from the relative motion between a vehicle body and its wheels. This published application, however, requires a conventional shock absorber to provide the necessary damping function. Further, this application lacks a capacitive reservoir in the hydraulic circuit that is necessary for an operative system.
It is therefore an object of the present invention to provide a regenerative shock absorber that not only recovers energy from the reciprocating motion of a vehicle's suspension system, but also provides the damping function so as to make unnecessary a separate shock absorber.